Feature: Per-project cumulative usage tracking (tokens, cost, time)

Problem

There's no way to see cumulative Claude Code usage across sessions for a given project. The /cost command shows current session usage, but nothing persists or aggregates.

Use Case

We're a small dev team using Claude Code heavily for internal tooling. We'd love to include AI usage stats in our PR descriptions, sprint reports, and dev documentation — things like:

• "This feature took 4 Claude sessions and 3.2M tokens"
• "ProjectHub has consumed 45M tokens across 127 sessions since March"
• Token burn rate per project per week

This would help us understand the ROI of AI-assisted development and make for interesting engineering metrics.

Proposed Solution

Persistent per-project usage tracking that records after each session:

• Total input/output tokens
• Estimated cost
• Session duration (wall-clock)
• Session count
• Timestamp

CLI access:

# Show usage for current project
claude usage

# Show usage for a specific project  
claude usage --project /path/to/project

# Export as JSON for dashboards/reporting
claude usage --json

# Show usage for last 30 days
claude usage --since 30d

Storage: A .claude/usage.json (or similar) in the project directory, or centralized in ~/.claude/usage/.

Bonus: Expose via an API or hook so it could be pulled into PR templates, CI dashboards, or team reports automatically.

Alternatives Considered

• Manually tracking with a JSON file (works but lossy and tedious)
• Parsing /cost output at end of each session (not automatable)
• Git commit frequency as a proxy (very indirect)

Additional Context

The data is already being computed per-session (visible via /cost). This request is really just about persisting it and making it queryable across sessions.

🤖 Generated with Claude Code